Sweden’s Supreme Court on Thursday upheld a court order to detain WikiLeaks founder Julian Assange for questioning over allegations of rape and sexual molestation.

The 39-year-old Australian, who denies the accusations made by two Swedish women after his visit to the country in August, had appealed two lower court rulings allowing investigators to bring him into custody and issue an international arrest warrant.

He has not been formally charged.

WikiLeaks has angered the U.S. and other governments by publishing almost half a million secret documents about U.S. diplomatic relations and the wars in Afghanistan and Iraq.

The search for Assange, whose whereabouts are unknown, was stepped up Wednesday as Sweden confirmed it had issued a European arrest warrant for him. Since leaving Sweden, the computer hacker has appeared in Britain and Switzerland but disappeared from public view after a Nov. 5 press conference in Geneva. He has spoken publicly only through online interviews.

The Supreme Court in Stockholm only reviews cases that are of importance for the interpretation of Swedish law or in exceptional cases where circumstances merit such a review.

It said it saw no reason to review the Assange case and upheld the detention order. The previous court order had stated that Assange is suspected of rape, two counts of sexual molestation and one count of unlawful coercion.

Assange’s attorney in Britain, Mark Stephens, said he would challenge any eventual British arrest warrant in court.

“The process in this case has been so utterly irregular that the chances of a valid arrest warrant being submitted to me are very small,” he told The Associated Press in a brief telephone interview Thursday.

Stephens, a prominent British media lawyer who also represents the AP, said he wasn’t prepared to detail the nature of any possible legal challenge as he had yet to be served with a warrant.